1 files changed, 60 insertions, 0 deletions
diff --git a/gnuradio-core/src/lib/general/gr_head.cc b/gnuradio-core/src/lib/general/gr_head.cc
new file mode 100644
index 000000000..7771ed515
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_head.cc
@@ -0,0 +1,60 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <gr_head.h>
+#include <gr_io_signature.h>
+
+gr_head::gr_head (size_t sizeof_stream_item, int nitems)
+  : gr_sync_block ("head",
+		   gr_make_io_signature (1, 1, sizeof_stream_item),
+		   gr_make_io_signature (1, 1, sizeof_stream_item)),
+    d_nitems (nitems), d_ncopied_items (0)
+{
+}
+
+gr_block_sptr
+gr_make_head (size_t sizeof_stream_item, int nitems)
+{
+  return gr_block_sptr (new gr_head (sizeof_stream_item, nitems));
+}
+
+int
+gr_head::work (int noutput_items,
+		    gr_vector_const_void_star &input_items,
+		    gr_vector_void_star &output_items)
+{
+  if (d_ncopied_items >= d_nitems)
+    return -1;				// Done!
+
+  unsigned n = std::min (d_nitems - d_ncopied_items, noutput_items);
+  
+  if (n == 0)
+    return 0;
+
+  memcpy (output_items[0], input_items[0], n * input_signature()->sizeof_stream_item (0));
+  d_ncopied_items += n;
+
+  return n;
+}